At present, a battery of a tablet computer is mainly used for supplying power to a display panel, an internal processor and circuit. The voltage of the battery is relatively small, and a corresponding current is generally not larger than 500 mA.
Usually, an external device connected with the tablet computer, for example, by an On The Go data line (OTG line), also requires power being supplied from the tablet computer. However, when an external device with a charging current of more than 500 mA requires power being supplied from the tablet computer, the current that is less than 500 mA usually cannot supply power to the internal processor and circuit and charge the external device simultaneously.